Intelligent robots must be able to perform safe and efficient motion planning in their environments. Central to modern motion planning is the configuration space. Configuration spaces define the set of configurations of a robot that result in collisions with obstacles in the workspace, C-clsn, and the set of configurations that do not, C-free. Modern approaches to motion planning first compute the configuration space and then perform motion planning using the calculated configuration space. Real-time motion planning requires accurate and efficient construction of configuration spaces. We are the first to apply a convolutional encoder-decoder framework for calculating highly accurate approximations to configuration spaces. Our model achieves an average 97.5% F1-score for predicting C-free and C-clsn for 2-D robotic workspaces with a dual-arm robot. Our method limits undetected collisions to less than 2.5% on robotic workspaces that involve translation, rotation, and removal of obstacles. Our model learns highly transferable features between robotic workspaces, requiring little to no fine-tuning to adapt to new transformations of obstacles in the workspace.

Tensors in the form of multilinear arrays are ubiquitous in data science applications. Captured real-world data, including video, hyperspectral images, and discretized physical systems, naturally occur as tensors and often come with attendant noise. Under the additive noise model and with the assumption that the underlying clean tensor has low rank, many denoising methods have been created that utilize tensor decomposition to effect denoising through low rank tensor approximation. However, all such decomposition methods require estimating the tensor rank, or related measures such as the tensor spectral and nuclear norms, all of which are NP-hard problems. In this work we leverage our previously developed framework of $\textit{tensor amplification}$, which provides good approximations of the spectral and nuclear tensor norms, to denoising synthetic tensors of various sizes, ranks, and noise levels, along with real-world tensors derived from physiological signals. We also introduce two new notions of tensor rank -- $\textit{stable slice rank}$ and $\textit{stable }$$X$$\textit{-rank}$ -- and new denoising methods based on their estimation. The experimental results show that in the low rank context, tensor-based amplification provides comparable denoising performance in high signal-to-noise ratio (SNR) settings and superior performance in noisy (i.e., low SNR) settings, while the stable $X$-rank method achieves superior denoising performance on the physiological signal data.

While much research focused on producing explanations, it is still unclear how the produced explanations' quality can be evaluated in a meaningful way. Today's predominant approach is to quantify explanations using proxy scores which compare explanations to (human-annotated) gold explanations. This approach assumes that explanations which reach higher proxy scores will also provide a greater benefit to human users. In this paper, we present problems of this approach. Concretely, we (i) formulate desired characteristics of explanation quality, (ii) describe how current evaluation practices violate them, and (iii) support our argumentation with initial evidence from a crowdsourcing case study in which we investigate the explanation quality of state-of-the-art explainable question answering systems. We find that proxy scores correlate poorly with human quality ratings and, additionally, become less expressive the more often they are used (i.e. following Goodhart's law). Finally, we propose guidelines to enable a meaningful evaluation of explanations to drive the development of systems that provide tangible benefits to human users.

This article was featured in One Great Story, New York's reading recommendation newsletter. Sign up here to get it nightly. But before Microsoft's Bing started cranking out creepy love letters; before Meta's Galactica spewed racist rants; before ChatGPT began writing such perfectly decent college essays that some professors said, "Screw it, I'll just stop grading"; and before tech reporters sprinted to claw back claims that AI was the future of search, maybe the future of everything else, too, Emily M. Bender co-wrote the octopus paper. Bender is a computational linguist at the University of Washington. She published the paper in 2020 with fellow computational linguist Alexander Koller. The goal was to illustrate what large language models, or LLMs -- the technology behind chatbots like ChatGPT -- can and cannot do. Say that A and B, both fluent speakers of English, are independently stranded on two uninhabited islands. They soon discover that previous visitors to these islands have ...

To celebrate International Women's Day, we take a look back over the past year and highlight some of the women we've interviewed, written about, chatted to, and featured on AIhub. Rose Nakasi is a Lecturer of Computer Science and a Research Scientist at the Makerere Artificial Intelligence Lab, in Makerere University, Uganda. She holds a PhD in Computer Science from Makerere University. Her research interests are in artificial intelligence and data science, and particularly in the use of these for developing improved automated tools and techniques for microscopy diagnosis of diseases like malaria in low-resourced but highly endemic settings. We spoke to Rose Nakasi about her work developing machine learning techniques to aid diagnosis of microscopically diagnosed diseases: Interview with Rose Nakasi: using machine learning and smartphones to help diagnose malaria.

South Africa's Emoyamed Hospital has experienced a stunning 180% revenue growth within just three months of adopting cutting-edge AI and ChatGPT technology. The hospital's new Board of Directors and Management team have also leveraged the power of the 3-I's model – Integrity, Innovation, and Impact – to transform patient care and outcomes. Emoyamed Hospital in Bloemfontein, South Africa, has pivoted from old systems and embraced AI and ChatGPT to build better patient care and financial systems. These new technology innovations have allowed the hospital to serve a larger patient population and expand rapidly. In just two months, the hospital was authorized by the Free State Department to open 57% more beds, a remarkable feat that speaks to the effectiveness of the new AI decision-making systems for patient and system-management protocols. According to Professor Terrence Kommal, the Executive Chairman of Emoyamed, the new board and management team are "rooted in servant leadership and have a deep empathy for humanity."

Understanding the meaning of words in context is fundamental for reading comprehension. The perceived difficulty, hereafter referred to as complexity, of a target word within a given text varies widely among readers. With an increased demand for distance learning and educational technologies[107], research into automatically predicting which words are likely to cause comprehension problems is becoming a popular area of research [115, 147, 185]. Systems have been created to identify complex words that are difficult to acquire, reproduce, or understand for children [79], second-language learners [89], people suffering from a reading disability, such as dyslexia [131] or aphasia [35, 53], or more generally, individuals with low literacy [59, 175]. In Computational Linguistics and Natural Language Processing (NLP), the task of automatically recognizing complex words is most often achieved by training machine learning (ML) models. These ML models assign a complexity value to each target word within an inputted extract, sentence, or text that allows for the identification of complex words. This information can then be used to improve downstream lexical and text simplification systems that provide simpler alternatives to aid reading comprehension. Take the extract shown in Table 1 for example.

The statistical modeling of random networks has been widely used to uncover interaction mechanisms in complex systems and to predict unobserved links in real-world networks. In many applications, network connections are collected via egocentric sampling: a subset of nodes is sampled first, after which all links involving this subset are recorded; all other information is missing. Compared with the assumption of ``uniformly missing at random", egocentrically sampled partial networks require specially designed modeling strategies. Current statistical methods are either computationally infeasible or based on intuitive designs without theoretical justification. Here, we propose an approach to fit general low-rank models for egocentrically sampled networks, which include several popular network models. This method is based on graph spectral properties and is computationally efficient for large-scale networks. It results in consistent recovery of missing subnetworks due to egocentric sampling for sparse networks. To our knowledge, this method offers the first theoretical guarantee for egocentric partial network estimation in the scope of low-rank models. We evaluate the technique on several synthetic and real-world networks and show that it delivers competitive performance in link prediction tasks.

This paper presents a scalable online algorithm to generate safe and kinematically feasible trajectories for quadrotor swarms. Existing approaches rely on linearizing Euclidean distance-based collision constraints and on axis-wise decoupling of kinematic constraints to reduce the trajectory optimization problem for each quadrotor to a quadratic program (QP). This conservative approximation often fails to find a solution in cluttered environments. We present a novel alternative that handles collision constraints without linearization and kinematic constraints in their quadratic form while still retaining the QP form. We achieve this by reformulating the constraints in a polar form and applying an Alternating Minimization algorithm to the resulting problem. Through extensive simulation results, we demonstrate that, as compared to Sequential Convex Programming (SCP) baselines, our approach achieves on average a 72% improvement in success rate, a 36% reduction in mission time, and a 42 times faster per-agent computation time. We also show that collision constraints derived from discrete-time barrier functions (BF) can be incorporated, leading to different safety behaviours without significant computational overhead. Moreover, our optimizer outperforms the state-of-the-art optimal control solver ACADO in handling BF constraints with a 31 times faster per-agent computation time and a 44% reduction in mission time on average. We experimentally validated our approach on a Crazyflie quadrotor swarm of up to 12 quadrotors. The code with supplementary material and video are released for reference.

Reprints will not be available from the author(s). ABSTRACT Objectives: We hypothesize that multistate models are beneficial in analyzing transitions through kidney states and understanding the underlying processes influencing the course of kidney health. Specifically, we aim to quantify longitudinal acute kidney injury (AKI) trajectories and to describe transitions through progressing and recovery states and outcomes among hospitalized patients. Methods: In this large, longitudinal cohort study, 138,449 adult patients admitted to a quaternary care hospital between January 2012 and August 2019 were staged based on Kidney Disease: Improving Global Outcomes (KDIGO) serum creatinine criteria as No AKI, Stage 1, Stage 2, Stage 3, and Stage 3 with renal replacement therapy (RRT) AKI for the first 14 days of their hospital stay. We fit and examined multistate models to estimate probability of being in a certain clinical state at a given time after entering each one of the AKI stages. We investigated the effects of age, sex, race, admission comorbidities, and prolonged intensive care unit (ICU) stay on transition rates via Cox proportional hazards regression models. Results: Twenty percent of hospitalized encounters (49,325/246,964) had AKI; among patients with AKI, 66% (n = 32,739) had Stage 1 AKI, 18% (n = 8,670) had Stage 2 AKI, and 17% (n = 7,916) had AKI Stage 3 with or without RRT.